Hugh Hefner is extremely sick and weighs an unhealthy 90 pounds, say sources close to the Playboy founder. (Instagram)

Hugh Hefner is frail and weighs a sickly 90 pounds, say sources close to the Playboy founder.

The situation has gotten so dire that some fear Hefner is close to death.

Hef and his inner circle are desperately trying to keep his poor health a secret.

“He looks like he is down to around 90 pounds and super sick,” a source told Page Six. “His people are really trying to keep this under wraps. You even have to sign a confidentiality agreement to go up to see him.”

British model Carla Howe, who visited Hef last year, was shocked by how frail he had gotten.

“Hef is so frail, he goes everywhere with a group of nurses,” said Howe, who said Hefner “never leaves homes” and goes to bed every night at 9 p.m.

Hef’s rep insist the media icon is well, but admitted he has health issues due to his age.

“Hugh Hefner is fine,” said a Playboy rep. “It is no secret that over the past few years he has suffered with back pain, but at 90 years of age he is enjoying his life and still very involved in the day-to-day activities of editing the magazine.”

Hefner sold the Playboy Mansion for $100 million in August 2016, and has been married to former Playboy Playmate Crystal Harris since 2012.

Holly Madison participated in group sex orgies with Hugh Hefner’s other girlfriends from 2001 to 2008. Holly’s role as ‘No. 1 girlfriend’ was to have anal sex with Hef. (Instagram)

In 2015, Holly Madison (who dated Hef from 2001 to 2008), slammed Hugh Hefner as a manipulative sexual predator who drugged and took advantage of naive young women.

Madison said she got so depressed over her shallow life with Hef she once considered killing herself in the bathtub.

“If I just put my head under water and take a deep breath in, it would all be over,” Holly wrote in her tell-all book, Down the Rabbit Hole.

“I don’t think he cared if we enjoyed sex. But I don’t think he cared about my happiness at all.”

Holly, who wanted to marry and have children with Hefner, said Hef often pitted the girls against each other to create petty rivalries so he could keep his young harem under his thumb.

Hugh Hefner’s son, Cooper Hefner, said Madison as a bitter, opportunistic gold digger who used Hef for money and fame.